WASHINGTON -- The Bush administration has revised the charter of a federal advisory committee concerned with the safety of research volunteers to specify that embryos and fetuses in experiments are "human subjects" whose welfare deserves special attention.

The change does not give embryos used in research any particular protections or have any direct impact on federal policy. But it is another indication that the administration considers embryos and fetuses to have special rights.

The committee, whose members have yet to be appointed, will offer recommendations to the Health and Human Services Department. The agency would have to propose regulations or encourage legislation if it wanted to put new protections in place.

The change was made to recognize that certain populations are particularly vulnerable in today's research, said Arthur Lawrence, deputy assistant secretary for health...